With highly industrialized development and fast increase of population, the treatment of waste water has become an important issue for modern cities. When using ozone to reduce the COD in waste water by oxidizing organics containing oil, fatty oil, etc., the most common primary products are organic acids, alcohols, or aldehydes, depending on the rate of oxidization reaction. Please refer to International Ozone Symposium Proceedings 21-22 Oct. 1999, Basel. In these cases, the COD has only been marginally lowered. If an attempt to continue the oxidation reaction until the organic acids, alcohols, and aldehydes are further oxidized into carbon dioxide and water is desired, the reaction process will be slow and a large amount of ozone will be consumed. Advanced oxidization processes, such as the use of hydrogen peroxide with ozone, the use of UV radiation with ozone, and the use of catalysts with ozone, are generally able to increase the reaction rate of the oxidization process for the treatment of waste water. However, these processes cannot lower the ozone consumption, and often add greatly to the total cost.
In view of the known technologies, the present invention provides a new and ozone-saving method to treat organics-containing waste water. That is, when organic acid intermediates are formed from the oxidization of organics by ozone, they chelate with valent ions dissolved in water and precipitate from the waste water, so as to reduce the amount of ozone consumed and greatly achieve the purpose of cost-saving.